A data processing apparatus processes an incoming data stream in order to ascertain or calculate output data therefrom. Known examples of a data processing apparatus include a circuit architecture with logic gates, such as a digital signal processor (DSP).
Particularly in a digital data transmission system such as a mobile radio system, a data processing apparatus is used in a receiver apparatus, for example. The data processing apparatus has at least one processor which is used to ascertain information contained in incoming data. Since a large number of different algorithms or methods can be used to ascertain the information, the data processing apparatus often contains a large number of processors operating in parallel or in series, which process the incoming data stream independently or in parallel with one another.
In mobile digital data transmission systems, including in a UMTS mobile radio system, the data processing apparatus processes incoming data which have been transmitted at different data transmission rates or with different transmission properties for the transmission channels. The transmission properties can change very quickly over time. This means that during particular periods there is a condition during which a processor processes the incoming data even though the output data which it provides are not used further. The data processing apparatus consumes power as a result of its switching the logic gates or blocks contained in the processors. This unnecessary power consumption has the associated drawback, particularly in mobile data transmission systems, that the limited resource of a power supply belonging to the data processing apparatus is subjected to unnecessary load.
To overcome this drawback, individual processors are usually decoupled from the power supply for the period in which they process data which are not associated with them. In this case, the processor is in a quiescent condition. In data transmission systems with poor or constantly changing quality for the transmission channels, the operating condition of a processor can quickly change from a quiescent condition to an operating condition, however. Since, when the processor is coupled to the power supply, a turn-on time is required until this processor operates reliably, the aforementioned measure cannot always be used. The aim of looking after the resources of the power supply to a large extent is not fulfilled in optimum fashion.